376 EXPERIMKNTS ON THK COMPOSITION OF WHEAT GRAIN. 
of wheat grain, has engaged the attention of many scientific observers. 
MM. Boussingault, J. Pierre, and Eeiset, abroad^ and Messrs. Lawes 
and Gilbert, in this country, have added several important facts to oiu' 
knowledge of the variations in the yield and quality of corn under 
different conditions of cidture and of atmospheric iniluence, and also 
according to the particular variety of seed grown. There were still 
several points to be cleared up, and it is to one among these that my 
attention has been more particularly directed since the autumn of 
1863- It is the relation of the density of the seed to its chemical 
compositiouj and to its germinating and productive powers, that I 
have submitted to an experimental investigation. The first portion of 
my results has been already published,* and a brief account of some of 
those more recently obtained may prove of interest to the readers of 
the ' Journal of Botany.* 
Most samples of dressed wheat grain, if carefully examined, will be 
found to consist partly of hard, horny, subtranslucent grains, partly of 
softer opaque floury grains, and partly of grains presenting a mixed 
aspect. I have specially examined two varieties of wheat, and the pro- 
portions of the three sorts of grain which my samples contain are given 
Iiere in percentages ; — 
Hallett's white rough 
Spalding : red wheat (1864). chaffed (1865). 
Translucent «... 49 per cent. 24 per cent. 
Medium . . . . , 34 „ 31 „ 
Opaque .17 „ 45 „ 
These proportions fluctuate, however, even with the same variety of 
wheat under the various conditions of season, maturity when cut, etc. 
It is not, however, these proportions that I wish to discuss,- but a re- 
markable difference in composition between the translucent and the 
opaque grains. I am aware that previous observers have detected cer- 
tain chemical diflferences between the poor shrivelled grains and the 
full plump grains. But the grains which I find to offer a most striking 
contrast as to the proportions of their most important constituent, 
present no striking contrast in size, shape, or weight. In Hallett's 
white wheat, for instance, the 24 translucent grains weigh ]9 grs. ; 
the 45 opaque grains weigh 34*2 grs. Had the opaque grains been of 
exactly the same density and size as the translucent grains, their weight 
* 'Practice with Science,' part i. p. 101. (Longiuana, 1865). 
